Solder for aluminum and aluminum alloys



Patented Feb. 28, 1928.

UNITED STATES GOTTHILF sonormr; or srur'rean'r, GERMANY.

SOLDER FOR AIZUMIHUM AND ALUMINUM ALLOYS.

No Drawing. Application filed June 14, less, Serial No. 116,018, and inGermany June 15, 1925.

This invention relates to a process for the production of a solder foraluminum and aluminum alloys, having up to 70 per cent aluminum alloyedwith tin,;zinc, cop- 5 per, iron, silicon, and lithium or the alloy,consisting of to 14: parts of silicon in aluminum, known as silumin. Thepercentage of aluminum may be variedbetween 30 and 70 per cent aluminum.The tin and 10 zinc content may be altered at times in a correspondingmanner, for instance in the ratio 1:2 in order to adapt the degree offluidity of the solder to different types of articles, such as castingsor sheets.

l v To make. up 1 kgm. weightof the solder according to the invention,we may use 450 gm. aluminum.

. 370 gm. tin.

180 gm. zinc.

gm. copper.

'15 gm. silicon.

10 gm. lithiumor silumin.

5 gm. iron.

From these constituents, about '1 kgm. of the aluminum solder will beobtained in the final alloyed condition.

The solder may be produced in the following manner. The copper is firstmeltedtogether with an equal weight of aluminum, in order to produce analloy of lower melting point than the copper itself. The copper-aluminumalloy thus produced is then melted together with the iron and silicon.These constituents are thoroughly mixed, and the remainder of thealuminum, the zinc, tin, and lithium or silumin are added in turn to thefluid mass. c

In order to clean the molten mass, or to remove theoxides therefrom, achloride, for instance iron chloride, is added in very small quantities.By these 'means after quite a short time a dry mass of scum and slagseparates on the surface of the fluid metal, and may be skimmed ofi,leaving the liquid clean and clear.

The solder has several advantageous.

properties. Its constitution renders it able to unite uniformly. withthe metal. to be soldered. It may be particularl empha- 5 sized that theplaces be solde solder and the aluminum.

' instance,

a soldering iron.

need not be specially prepared beforehand by removing the oxide fllm,and no special binding agent is necessary. There is thus very littledifference of electrical potential between the soldered positions andthe aluminum. The soldered place is thus not subject to disintegration,as is the case with known solders. The soldering will last so a muchlonger, as is known, the smaller the electrical potential differencebetween theo When cold, the solder is characterized especially byitsgreat adhesion and extreme strength. For

a tensile strength --of' up ,to' 865kg/cm is obtained with solderedparts. 7 The tensile strength of rods produced entirely ofsolderis, incomparison, very much greater. i y No cracks occur, in the completedsolder--- ing, as has hitherto often been the case, 7 this freedom fromcracking being. due to the relatively low working temperature, which maybe about 450. The soldered places may furthermore be highly polished,

and will retain this polish; the solder may be given any desired tone,to correspond to that of the. article soldered by slight modificationsof the quantities of the added material, for instance, 'ofthe copper.

The properties of the solder render it-posa5 sible to solder on and tomould pieces which have been broken off from objects, and parts whichare to be specially applied, such as flanges, arms, ribs, pipes, eyes,and the like. Ali important economical advantage, is thusprocured,since, for instance faulty castings. may be again made usable.

The solder may be used in such a way that, for instance with strongaluminum sheet a solder whic is not very fluid is applied by means of asoldering pistol, whereas with weak aluminum sheet, a readily fluidsolder is applied by'means of a blast The process renders possible theproduction of "a series of solders from which a solder may be selectedwhich will be entire-' 1 suitable for the metal to be soldered, sovthatin all cases a satisfactory soldering can be produced. 7

The quality of the solder is not intrinsi- A solder for aluminum andaluminum alcally altered if silumin be used instead of loys consistingof 450 parts aluminum, 370 10 lithium. parts tin, 180 parts zinc, 20partscopper, 15

As no' lead is present in the solder,'-and parts of silicon, 10 parts oflithium or 5 also no other deleterious constituents, the silumin, and 5parts of iron, as set forth.

solder is particularly suitable for the repair In testimony whereof Ihave signed my of damaged aluminum domestic articles. name to thisspecification.

What I claim is: GOTTHILF SCHULDT-

